基于分层PCE的多域最小代价路径启发式算法

智能光网络技术和P2MP（点对多点）技术的融合将能够极大地促进光组播业务的发展。文章针对多层多域光网络中的P2MP业务,提出了一种MDMPH（基于分层PCE（路径计算元素）的多域最小代价路径启发式）算法,并进行了仿真分析。与传统的PDB（基于逐域路径）算法、E-BRPC（基于扩展的反向回溯）算法以及CTB（基于核心树）算法相比,MDMPH算法能够计算出代价更小的P2MP路径树

坡面侵蚀过程中泥沙有机碳流失特征分析

以野外布设的径流小区为研究对象，采用模拟降雨方法研究随机条件下降雨侵蚀过程中泥沙有机碳 含量及流失过程的动态变化规律。结果表明：（１）降雨侵蚀过程中泥沙有机碳含量随降雨的进行逐渐降低 并趋于平稳，与坡面土壤有机碳含量相比显著增高（ｐ＜０．０１），有机碳在泥沙中明显富集，富集比最大值达 １．７８０，泥沙中有机碳含量及富集比随侵蚀速率的增加明显减小且趋于稳定；（２）泥沙有机碳流失速率随降 雨的进行先波动增大，达到最大值后又波动减小，最后逐渐趋于准稳定，整个过程呈单峰分布；（３）泥沙有 机碳流失强度与土壤侵蚀强度呈显著性线性正相关（ｐ＜０．０１），说明土壤侵蚀量决定侵蚀过程中有机碳流 失量，准确获取土壤侵蚀强度是估算坡面有机碳流失量的基础。 关键词：坡面侵蚀；模拟降雨；土壤有机碳流失.</p

UAV target tracking algorithm based on event camera(基于事件相机的无人机目标跟踪算法)

无人机目标跟踪可应用于消防、军事等重要领域，已成为计算机视觉领域热门研究课题之一。现有的无人机目标跟踪算法大多基于传统RGB相机结合深度学习算法，但此类算法一方面无法避免无人机机体抖动造成的运动模糊，另一方面因传统RGB相机在低光照或过曝光场景下成像质量较差，难以跟踪目标，为此提出采用无人机搭载DAVIS事件相机的方法进行目标跟踪。设计了基于事件与灰度图的双模态融合跟踪网络，用Vicon运动捕捉系统制作了无人机视角下的目标跟踪Event-APS 28数据集，实现了在复杂光照场景下对目标物的有效跟踪

Synthesis and characterization of twinned flower-like ZnO structures grown by hydrothermal methods

Twinned flower-like ZnO structures have been synthesized by one-step (TAB assisted hydrothermal methods at a low-temperature as 90 degrees C. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) results disclosed a twinned flower-like morphology and hexagonal wurtzite structures. The XRD pattern and temperature-dependent PL results show a mixed structure of as-grown samples, which are confirmed by the SEM results. The CL spectrum on a single twinned flower-like ZnO structures showed an excellent optical property. Based on experimental results, self-etching and regrowth are suggested as the mechanism to grow the flower-like structures. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved

Double disks shaped ZnO microstructures synthesized by one-step CTAB assisted hydrothermal methods

Double disks shaped ZnO microstructures have been synthesized by one-step CTAB assisted hydrothermal methods at 90 degrees C with different growth time. The scanning electron microscopy (SEM) and X-ray diffraction (XRD) results disclosed the double disks shaped morphology and hexagonal wurtzite structures. With the increase of growth time, the strain along a axis becomes relaxed while that along c axis becomes more compressed. This made the increase of defect-related visible emissions and the decrease of UV near-band-gap emissions. Based on the experimental results, surfactant (CTAB) and growth temperature are suggested as the key factors for the formation of the double disks shaped ZnO. A possible growth mechanism to form the double disks shaped ZnO have been provided. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved

Effects of Sulfur Introduction on the UV and the Visible Emission Properties of ZnO

Hexagonal ZnO particles have been synthesized by using the hydrothermal method with different sulfur concentrations in the reaction solutions. Structural and optical characterizations have been conducted to study the effects of the sulfur in the reaction solutions on the properties of the synthesized ZnO in the ultraviolet (UV) and the visible (VIS) bands. The existance of sulfur in the solutions can help to introduce compression strain along the a axis and an opposite trend for the parameter c with strain inside the formed ZnO particles, which means the total strain in the samples is presented along the c axis. The average size of the ZnO particles, as calculated from SEM images, shows the same trend as the strain in the samples. The increasing incorporation of sulfur causes an increase in the VIS luminescence band, which can be attributed to an increase in the number of sulfur-induced defects

近70年来中国自然地理与生存环境基础研究的重要进展与展望

自然环境是人类赖以生存和发展的基础,探索自然环境及其各要素(如地貌、气候、水文、土壤等)的特征、演变过程、地域分异规律以及驱动机制是自然地理学的重点研究内容.中国自然地理要素类型丰富且区域差异较大,为开展自然地理研究提供了难得的机遇.文章主要围绕青藏高原隆升与亚洲内陆干旱化及河流发育、高原冰冻圈环境演化、全新世多时间尺度季风与西风气候变化、湖泊与湿地、流域模型与土壤侵蚀、过去人-地关系演化、生物地理及中国三维地带性规律等几个方面,梳理了近70年来中国自然地理与生存环境研究的重大理论进展与重要贡献.在简要交代国际前沿研究进展的基础上,回顾并梳理了中国自然地理学各分支领域的研究脉络,进一步聚焦重大研究成果或具有较大争议、重大影响的学术争鸣问题,归纳目前研究现状,并进行未来工作展望.最后提出在推进生态文明建设的国家需求下,应发挥中国自然地理研究的优势,厘清自然地理要素变化的过程、规律与机制,持续推进中国自然地理研究为国家战略服务,在全球视野下做出具有中国特色的自然地理学理论贡献

A High Power InGaN-Based Blue-Violet Laser Diode Array with a Broad-Area Stripe

An array of high power InGaN/GaN multi-quantum-well laser diodes with a broad waveguide is fabricated. The laser diode structure is grown on a GaN substrate by metal-organic chemical vapor deposition. The laser diode array consists of five emitter stripes which share common electrodes on one laser chip. The electrical and optical characteristics of the laser diode array are investigated under the pulse current injection with 10 kHz frequency and 100 ns pulse width. The laser diode array emits at the wavelength of 409 nm, which is located in the blue-violet region, and the threshold current is 2.9 A. The maximum output light peak power is measured to be 7.5 W at the wavelength of 411.8 nm under the current of 25 A